Zinc base alloy



i No Drawing.

Patented June 20, 1933 JOHN R. FREEMAN, JR., 013

WATERB URY, CONNECTICUT, ASSIGNOR TO THE AMERICAN BRASS COMPANY, OF WATER-BURY, CONNECTICUT, A COIR-IPORATION 0F CONNECT- ICUT This invention relates to an alloy and in particular a zinc base alloy and more particularly a zinc base alloy for die casting. The new alloy disclosed herein has the special advantage that it combines high tensile strength with good ductility and impact strength together with a high'dcgree of permanence. It is to be noted that the alloy described herein may be made with zinc of usual commercial grade, but that it may also be made with zinc of the highest purity obtainable, and that the use of such high purity zinc will add to those superior properties generally associated with the use of such high purity zinc, for example superior corrosion resistance and improved casting properties. It is intended that this patent shall cover the alloy disclosed when thezinc used therein is either of the special high purity grade (99.98% zinc content) or the more widely used commercial grades such as High Grade No. 1 as specified by the American Society for Testing Materials.

I have discovered that zinc when alloyed with cadmium and copper has desirable properties for the production of castings of all types and more particularly die castings. In the use of these alloys of zinc cadmium and copper, I prefer to use an :11 loy containing from about 3 percent to 7 percent cadmium, and from about 0.25 per- Application filed November 23, 1931.

zmc Bless ALLOY Serial No. 576,950.

percent cadmium and 1 percent of copper, but may use alloys con taining from 0.50 to 15 percent cadmium and 0.25 to 10 percent copper depending upon the properties desired, the type of casting to be made and the use of the casting. It is preferred that the cadmium content be greater than the copper content because such alloys have superior casting qualities.

There is given in the table the results of tests which show the properties that may be obtained with the alloy. Zinc conforming to A. S. T. M. Specification No. B6--18 (high grade) was used in preparing the new alloy, data on which are given in the table. The test data given in the table were obtained on specimens conforming to the standard practice of Committee B-6 on Die Cast Metals and Alloys of the American Society for Testing Materials. For comparison, data are given also in the tableon a zinc base alloy which has been recommended for standard by the American Society for Testing Materials.

The superior stability of the new alloy is evident as indicated by permanence in physical properties and relative freedom from expansion when exposed to the severe test conditions of exposure to water vapor ticularly about 5 cent to 1.50 percent copper, but more parat 95 C. for ten days.

' Table Composition Physical properties Elongation in Average img z g 2 inches pact (b) percent ft. lbs. 0 d X a sion c) ZlIlC (lopper mium Round test bar in 6 v {telinches As east corro- After mar 1 As east c0rr0- As cast corrosion (0) sion New alloy remainder (d) 1. 42 3. 34 23170 27800 1. 3 2. 2 2. 64 2. 48 0. 0010 New alloy remainder (1i) 3. 1 4. 01 29550 29450 1. 8 l. 5 4. 42 2. 82 0010 New alloy remainder (d) 53 5. 79 24770 24730 2. 5 6. 8 4. 18 4. 56 0033 New alloy remainder (d) 1. 40 6. 41 26350 28050 2. 3 1. 8 3. 89 3 29 0020 New alloy remainder (d) 7. 10.71 31400 32800 1.0 1. 5 1.89 l 08 .0005

V Alumi- Magv 1111111 nesinm h A. S. T. M. High purity 2. 90 a 3.79 0.10 51520 4% 4.3 9 9.82 1.08 .0098

(a) Exposed to waterwapor at 95 C. for 10 days.

(12) Energy absorbed by square specimen-Chewy type of test bar.

(0) Measured over length of impact test bar casting. d) Zinc used equivalent to A. S. T. M. No. 1.

Having thus set forth the nature of my invention What I claim is:

1. A zinc base alloy containing from about 0.50 percent to about 15 percent cadmium, 5 from about 0.25 percent to about percent copper, and the remainder substantiallyall 2. A zinc base alloy containing from about 3 percent to 7 percent cadmium and from 10 about 0.25 to 1.5 percent copper, and the remainder substantially all zinc.

3. A zinc base alloy having a preferred composition of about 5 percent cadmium and about 1 percent copper, and the re- 1 mainder substantially all zinc.

4. A zinc base alloy containing from about 0.50 percent to about percent cadmium, from about 0.25 percent to about 10 percent copper with the cadmium content greater than that of the copper, and the remainder substantially all zinc.

In testimony whereof I afiix my signature.

JOHN R. FREEMAN, JR. 

